jfulford1

Hello.
I'm new to the LS world, coming from the small block/big block cars in the 70s and 80s.
I've got a bare block, .030 over from ATK. I have 799 heads currently getting a valve job, and LQ9 bushed rods. I also have the LQ9 cast crank currently being polished up.
'I'm looking for recommendations on cams and pistons for this build. The heads will have stock springs and I'm not running a converter(4L80 rebuilt, 2003 2500 truck). I'd like to make my power
below 5500. I have some ideas after looking/reading about these items, but there are way too many to choose from. Any help would be appreciated: Brands/combinations/etc.
I used to buy comp cams and sealed power pistons in the old days.
Trying to approach 500hp NA.
Thanks
jeff
2003 2500 Silverado longbed, 4wd, 4.10gears, 4l80, currently shorty headers.

G Atsma

A completely stock setup with a decent cam will easily make 500 HP.
Check with either Cam Motion, Texas Speed, and/or Summit for a cam. Tell them exactly what you have and how it will actually be used,and they will help you.

LS1 TJ

Piston wise I've used Diamond forged with great success. Manley forged rods. Cam wise Texas Speed have worked well for me. Having said that it seems like Summit has their own line of cams that seem to get good reviews and are a bit less expensive.
With any upgraded cam you will need new valve springs and push rods.
I know you don't want a converter but a 2800 stall would really wake up the combo. Get a Yank or Circle billet. Call either for their comments.
Good luck with your project.

Summitracing

OP,

We'd like to make cam and piston recommendations but need some more info first.

What is the intended use of the truck? Daily, tow rig, etc.

What fuel are you intending or willing to use?

Assuming this is fuel injected with the factory intake?

Would you be willing to step up to a .550" or .600" lift beehive spring?

Having these questions answered will help us narrow down recommendations.

Ls7colorado

iTrader: (3)

Id run a piston that will keep you around 10:5 or 11:1 compression run premuim and make sure the tune is good.
If your not willing to replace the valve springs or converter or rev passed 5500 then you will never even get close to 500HP
Best bet would be the NSR truck Norris cam, that might get you to the mid to high 300's to the tire

TurboBuick6

iTrader: (2)

Mill the heads, run a stock LQ9 piston with reliefs cut and a truck cam from the above mentioned vendors. Will not make 500 unless you go forced induction but should make some good torque numbers which is what you really want in a truck. Also, upgrade springs and trunions regardless to something quality.

Kjduvall

Im helping a friend put together a 01 2500hd right now, and our goal is to make a good bump in power but maintain drivability and towing while also sticking to a budget. so just for some thing to look at here is our set up. stock lq4 block .030 over, stock crank, ( stock rods/pistons/lifters/rockers/valves/bearings were trashed) so we are going with summit pro ls piston and rod kit sum-pr360302 that should put me in the 10.2 range with 317 heads (yours would be higher given your heads) and melling hi pressure/std volume oil pump, improved racing barbell, ls2 timing chain, tsp push rods (havent determined length yet) and tsp chopacabra cam 214/222 .550/.550 108lsa 106icl with the pac springs that come with it , morel drop in lifters with new trays and ws6 store rpm max effort rocker arms. clean up and rebuild the 317 heads then finish off with 52lb injecters,walbro 255 fuel pump, stock truck intake/stock ported throttle body and tsp 1 7/8 headers to a true dual 3in exhaust. the cam choice was based on stock converter and having a lumpy idle yet maintaining great drivability. i think we'll hit mid to high 300s as far as dyno goes in this heavy *** truck, op id be more concerned about a good overall package than trying to set a hp goal . ill post some dyno numbers and impressions of this setup when done just for fun (it might be awhile though)

Haggar

Don't take this wrong, but you are likely setting yourself up for disappointment if you are trying to achieve 500hp with those constraints. You aren't going to magically make power and keep so many things stock. Building a motor isn't necessary, a stock bottom end LQ4, LQ9, LS2, LY6, etc would be fine. But it seems you already have some of the parts.

If you want power, you need: 1) Compression 2) Cam duration / head flow 3) Displacement.
If you want 'perceived' power, you need to address transmission and gearing also.

I think you are limited on most of these, so you can only go so far. 450hp is more likely.

Decide what Compression Ratio that you can live with. This is going into a heavy 3/4 ton? You probably want to not go too much higher than 10.5-10.75 or so

Are you actually caring about HP, or more of a torque value?

If it was me, I would swap in a mild cammed LY6 and a 6L90e
If it was me I'd get a 4" crank and build a 408 stroker
If it was me, I would just put stock LQ4 overbore pistons in it, and run 862 or 706 '5.3' heads with a good valve job or full CNC porting. Would put your CR in the 10.5-10.8 range or so, depending on your finished chamber size. 799s will be OK too, if you keep dished stock pistons. With flat tops, they will be 11:1 and might be more than is good for your application. Flattops with square port heads would hurt you below 4000 rpm.

Run a cam in the 206-212 intake duration range. I would go in the .575 lift range and run beehives good for the lift.

I'd ditch the stock converter and run a quality aftermarket one with a higher than stock STR (stall torque ratio) to give more off the line performance.

jfulford1

Hello.
Thanks for the replay. My truck's primary use is like an older impala or chevelle with a bigblock: driving for fun, occasionly at the track.
I would still want to tow with it, but not very often and not heavy: a 5x8 wellls cargo covered trailer.
I am planning to use the factory truck intake, but willing to change injectors.
I could add beehive springs if necessary, but trying to keep the lift around 550-575.
This truck is sort of a consolation prize since I can't really afford what I used to have: a 71 nova and a 69 impala.
Currently, the truck is pretty much bone stock and runs great with 257K on it. Just wanting to add a bit more umph to it.
jeff

jfulford1

Willing to use premium(93 or so octane.
jeff

Haggar

In builds of this level, honestly, stock parts are fine. Its a bit different that what you'd be used to with older SBC/BBC.

So some stock replacements in the correct overbore size are likely fine. Check with forum vendor WS6Store, or with Summit Racing, both support the board and should have good parts for you. With 799 heads, you would normally end up with ~ 10.5 cr with dished LQ4 pistons, and 11:1 with flat top LS2/LQ9 pistons.

Highly suggest moving to a Trailblazer SS (TBSS) intake manifold. It will make more power everywhere in the rpm curve. If possible, get it with the stock TBSS LS2 injectors and rail as well. This will accept a 4 bolt 92mm throttle body.

Best way to wake up the off the line performance will be a properly selected high quality torque converter. This will increase your stall speed a bit to work with your new cam, but also will have more torque multiplication than stock, and likely take a few pounds of the super heavy stock converter.


For what it's worth, one of my personal swaps is a 1971 GMC. I have a 6.0 (LQ4) at stock 9.5:1 compression. I do have CNC'd 317 heads (This odd combo is due to previous owner of this long block running a blower). I run a TBSS intake, C6 LS2 injectors, 92mm throttle body, 1-7/8 headers. I run a 223/231 cam with ~0.630/0.615 lift. I have a 4L65e, Yank Pro-Truck 3200 converter, 4.56 gears, and I am on 33" tires on a 4" lift. I have never dragged it but it is a dead heat from 0 to 90mph with my friends C5 corvette. I've seen 0-60 times in the range of 4.6 - 4.8 seconds in my datalogs.

I'm currently planning to swap in an LSA blower and LS3 heads. If you want it to feel like a big block, that is the route to go.

gagliano7

https://www.high-performance-engines...uct-p/sp37.htm

Forcefed86

iTrader: (4)

What are you doing for fuel? Is E85 an option? Easiest option for 500+ HP “cheap” Is to run a .030 over hyper pop-up piston and get your compression up as as high as possible. Locals here run 14:1 on E85 with no issue. High compression with a decent cam on factory head will make 500 crank easily. A 4.8 at 14:1 Would make 500 easily and rev to 7800 with minimal parts. Also be dirt cheap to replace. Building big cube LS motors is cool, but not economical in my experience. I’d sell the 4” bore stuff and buy a baby motor. not to mention an alum 5.3 is 100lbs lighter.

If E85 isn’t an option, stick with a flat top hyper OEM style replacement from summit (or any parts house). Assemble it all stock with mild cam and decent beehive spring (pac 1218 etc) and run 100-175 shot of nitrous. Generally, you get 40-60hp over stock and the ability to rev it out to 7k with a cam/springs. Making power below 5500 or staying at 5500 and below isn’t beneficial unless you are towing. For a weekend warrior/toy you want RPM. Esp. if you did go with a power adder of any sort.

Anything more than that gets into $$. Better off with a power adder and cheap motors IMO. 500-600HP Turbo setup on a 4.8 is cheap when compared to a big bore 500-600hp built NA engine. You could replace that 6.0 with $500 4.8 liter and make 600-700hp easily with mild turbo parts. If the engine blows, just grab another and go. No machine shop time… very little down time and most of your turbo parts are re-useable. I get that’s not for everyone. Just thought I’d throw it out there. Its how I’ve been running 8’s and 9’s for years for what I consider “peanuts”. Esp. when compared to similar 8-9 sec cars.

Basic 6.0 build with 799. look at the curve above 5500.

You Tube

Summitracing

OP,

Thanks for replying with more info on your combo and goals.

We like what other folks are saying here. Stock replacement overbore pistons are plenty good for what you're looking to do here. Take a look at Sealed Power SLP-H1128CPA75MM dished pistons. These are stock replacement hypereutectic pistons for the Gen IV .943" pin floating rods. With those pistons, 799 heads, and .051" head gaskets you'd be right around 10:1 compression. We'd recommend some .040" Cometic head gaskets. That would bump compression up to around 10.3:1. The added bonus is these will reduce the quench distance. Reducing quench helps promote a more efficient combustion cycle and reduce the chance of knock. Pair those pistons with the Sealed Power SLP-E-921K30 rings.

If you wanted to up the compression more you could go with the Sealed Power SLP-H1129CPA75MM flat tops. With a .051" head gasket you would be around 10.8:1. Going with .040" head gaskets would bump that up to 11.1:1. Those would use the same ring set as above.

Then for a cam, we can see a couple of options.

The first one we'd look at is our SUM-8728R1 "Big Torkinator". Specs on it are .600/.585, 212/218, 110+3 with -5* of overlap. This will make great torque from 2,000 on up and pulls well to 6,500+ with our .600" lift beehives. The 8728R1 will have a steady lope but it's easy to tune and live with. This cam won't have a problem working with the stock stall converter.

The second cam we're thinking of is our SUM-8720R1 stage 2 high-lift truck cam. Specs on it are .600/.600, 218/227, 112+2 with -1* of overlap. This will have a steady lope but is easy to tune and live with. You would move your powerband a bit to the right from the 8728R1 and lose some low-end. You would make up for it in the mid-range and make more peak power. It pairs well with the same .600" lift beehives above. This is the largest cam we recommend for use with a stock converter.

We know our customers like combos so we've put together Pro LS cam combos. We have cam and spring combos or cam, spring, and install/gasket kit combos.

- For all 8728R1 combos check here.
- For all 8720R1 combos check here.

Let us know if we can be of any further assistance. We'll be happy to help.

grinder11

iTrader: (1)

^^^^This=Truth^^^^^ "Exactly" and "actually" are keywords here. OP, be honest with yourself. We've all probably imagined ourselves at a stoplight, idling away with enough Rockem-Sockem to shake up a can of paint!! The most important thing is to be honest with yourself as to how you'll actually drive the car the majority of the time, as Atsma pretty much covered. Done repeating him, before he files a plagiarism complaint!!!!

jfulford1

Thank you all for the advice/recommendations! I feel much better about what I am doing now.
I will post again when I'm getting all this together with the specs.
Again, Thank You!
Jeff

jfulford1

Ok, from all the advice and research, here is the list of my items I am currently building: ATK 13G8 Machined LQ4 6.0L Bare Block 4.030" 1299.00 plus 199.

Summit Racing™ Performance LS7 Hydraulic Lifters SUM-HT215-16 186.29

Melling Rocker Arms MR-1341 98.72

Sealed Power Plasma-Moly Piston Ring Sets E-921K30 78.99

Clevite P-Series Rod Bearings CB-663P(8) 30.99

Chevrolet Performance Oil Pumps 12710303 75.99

Cloyes Heavy-Duty Timing Sets C-3220 30.99

Fel-Pro Head Gasket Sets HS26192PT2 173.99

King SI-Series Main Bearings MB5293SI 38.99

COMP Cams Valve Springs 26906-16 99.95

BTR Valve Stem Seals VS LS HAT KIT 17.99

XFI RPM Camshaft GM Gen III/LS1/LS2/LS6 249-54-414-11 479.95

Engine Lifter Guide for Gen III 555-20850 6.79 x 4

Speed-Pro Hypereutectic Pistons H1129CPA .75MM 274.99

Apex Conversion/lower gasket set ACS3071 105.04

MELLINGMPR614 push rods 1.71 x 16

STANDARD MOTOR PRODUCTSPC278T CPS 25.79

GM GENUINE19300488 harmonic balancer 81.99

GM Genuine 12557840 harmonic balancer bolt 4.36

MAHLEGS33449 Head bolts, 2cnd design 27.79 x 2

Cam retention plate, Mahle 28.00

HEAD Rebuild, Phase II Performance, ‘799s 550.00

Crankshaft polished and checked, Phase II 125.00

I have finished the bottom end, measuring all involved.
Opinions on injectors?
Thanks again for all this help. I was a fish out of water with LS motors.
jeff​​​​​​​

Utinator

Any injector in the 38-42 lb/hr. range should work fine. I think the stock flex-fuel injectors are about 36 lb/hr. There are a few different part numbers.